Two cases preoccupy Roy Grace in James’s unnecessarily complicated eighth crime novel featuring the Brighton detective superintendent (after 2011’s Dead Man’s Grip). When a torso turns up in a vat of chicken excrement at a Sussex farm, Grace and his team know that the most important thing is to identify the victim, which proves difficult. Meanwhile, Grace eagerly awaits the birth of his first child (by his fiancée), though the memory of his first wife, who disappeared nearly a decade earlier, dampens his enthusiasm for fatherhood at times. Grace must also oversee the protection of pop superstar Gaia, who’s in Brighton to film her first serious movie, the story of George IV’s relationship with his secret mistress. That so many people wish the Lady GaGa-esque Gaia harm—including an obsessed Internet fan, whose love turns to rage when her idol ignores her—may strike some readers as implausible. Several side stories serve to confuse the main action. Agent: Carole Blake, Blake Friedmann Literary. (Dec.)